From: Shubhanshu Agrawal <shubhanshu@fb.com>
Date: Fri, 10 Nov 2017 01:35:30 +0000 (-0800)
Subject: adding a fibers compatible once flag
X-Git-Tag: v2017.11.13.00~7
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=commitdiff_plain;h=b529367b595dd4da7e70569cbea36d30ace4fa39;hp=b529367b595dd4da7e70569cbea36d30ace4fa39

adding a fibers compatible once flag

Summary:
The current folly::once_flag is not compatible with folly fibers
and when using it with fibers is inefficient and also cause deadlocks.

This diff makes the once flag's mutex be a templatable paramter
and overrides it in fibers library with a fiber compatible mtuex.

Reviewed By: yfeldblum

Differential Revision: D6288508

fbshipit-source-id: 6f82e1794d1f417f8d267061f1702a26a7b4ff12
---